Psychiatric human “inattention” brings about various obstacles to human's daily life. Here, another name “attention deficit” also exists for “inattention”, which is also referred to as “decline in attentional function” in cognitive science.
There are multiple neuropsychiatric diseases of which main symptoms are inattention. Among them, attention deficit/hyperactive disorder (hereinafter referred to as “ADHD”) is a neuropsychiatric disease affecting many humans regardless of age. According to previous studies, a prevalence rate of ADHD is said to be 5% or more. ADHD is classified as “predominantly inattentive type” and “predominantly hyperactive-impulsive type”, and in particular, the former is extremely difficult to find and diagnose. Nonetheless, considerable difficulties arise in social adaptation such as school and work depending on the symptoms. Thus, great expectations are gathered throughout the world for attempts to improve social outcome of children and persons with ADHD by early detection of inattention as well as by early diagnosis of ADHD, for example, by the National Institute of Mental Health (NIMH), etc.
In general, early detection and early diagnosis of ADHD is considered to be possible at the age of 3 to 6 years old. Diagnosis of ADHD, including attention deficit, is carried out by experienced pediatric neurologists, pediatric psychiatrists, or clinical psychologists, or by rating scales (questionnaires).
In the field of experimental psychology, comparative studies between ADHD children/persons and typically developing children/persons have been conducted using visual stimuli including visual search, in particular, feature search and conjunction search. Then, it has been reported that there is a delay specific to a child/person of ADHD, that is, a delay in reaction time until a prespecified target is found out (see, for example, Non-Patent Documents 1 to 3). Also, a delay specific to a child/person of ADHD has been reported similarly in Erichsen's Franker task and Stroop task which are tasks (visual stimuli) causing competition (for example, see Non-Patent Document 4).
In addition, a diagnosis support device for diagnosing autism using a device for measuring a gazing point of a subject is disclosed (Patent Documents 1 to 3).